Submitted to: Positive Strand RNA Virus International Conference Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 6/1/2004
Publication Date: 6/20/2004
Citation: Risatti, G.R., Kutish, G.F., Lu, Z., Holinka, L.G., French, R.A., Borca, M.V., Rock, D.L. 2004. The e2 glycoprotein of classical swine fever virus affects viral virulence in swine [abstract]. Positive Strand RNA Virus International Conference Proceedings. P. 109. Interpretive Summary: Poxvirus Meeting.
Technical Abstract: To identify genetic determinants of Classical Swine Fever Virus (CSFV) and host range, chimeras of highly pathogenic CSFV isolate Brescia and the attenuated vaccine strain CS were constructed from their respective infectious clones and evaluated for viral virulence in pigs. The chimeric Brescia/CS virus, 138.8v, containing the E2 glycoprotein and the non-structural proteins p7 and NS2-3 of CS in the Brescia background, exhibited unaltered growth characteristics on primary porcine macrophage cell cultures although a smaller plaque phenotype was observed on SK6 cell cultures. Notably, 138.8v was completely attenuated in pigs. Infection did however result in the rapid induction of a protective immune response in animals. Two additional viral chimeras were constructed to further define the genetic determinants responsible for 138.8v attenuation. Viruses 319.1v and 312.1v contained the CS E2 glycoprotein and the CS p7/NS2-3 genes in the Brescia background, respectively. 319.1v exhibited a similar attenuation phenotype in pigs as seen for 138.8v while 312.1v remained fully virulent. These results indicate a highly significant role for the E2 glycoprotein in pig virulence.